Traditional cigarettes deliver flavor and aroma to the smoker as a result of combustion, during which a mass of tobacco is combusted at temperatures which often exceeds 800.degree. C. during a puff. The heat of combustion releases various gaseous combustion products and distillates from the tobacco. As these gaseous products are drawn through the cigarette, they cool and condense to form an aerosol which provides the tastes and aromas associated with smoking.
Traditional cigarettes produce sidestream smoke during smoldering between puffs. Once lit, they must be fully consumed or be discarded. Re-lighting a traditional cigarette is possible but is usually an unattractive proposition to a discerning smoker for subjective reasons (flavor, taste, odor).
An alternative to the more traditional cigarettes includes those in which the combustible material itself does not itself release the tobacco aerosol. Such smoking articles may comprise a combustible, carbonaceous heating element (heat source) located at or about one end of the smoking article and a bed of tobacco-laden elements located adjacent the aforementioned heating element. The heating element is ignited with a match or cigarette lighter, and when a smoker draws upon the cigarette, heat generated by the heating element is communicated to the bed of tobacco-laden elements so as to cause the bed to release a tobacco aerosol. While this type of smoking device produces little or no sidestream smoke, it still generates products of combustion at the heat source, and once its heat source is ignited, it is not readily snuffed for future use in a practical sense.
Copending and commonly assigned, U.S. patent applications Ser. No. 08/380,718, filed Jan. 30, 1995, and Ser. No. 07/943,504, filed Sep. 11, 1992, disclose various heating elements and flavor generating articles which significantly reduce sidestream smoke while permitting the smoker to selectively suspend and reinitiate smoking. The former application issued Sep. 16, 1997, as U.S. Pat. No. 5,666,978, and the latter application issued Apr. 9, 1996, as U.S. Pat. No. 5,505,214.
The aforementioned, U.S. Pat. No. 5,666,978 describes an electrical smoking system including a novel electrically powered lighter and a novel cigarette that cooperates with the lighter. The preferred embodiment of the lighter includes a plurality of metallic serpentine heaters disposed in a configuration that slidingly receives a tobacco rod portion of the cigarette.
The preferred embodiment of the cigarette in U.S. Pat. No. 5,666,978 comprises a tobacco-laden tubular carrier, a cigarette paper overwrapped about the tubular carrier, an arrangement of flow-through filter plugs at a mouthpiece end of the carrier and a filter plug at the free (distal) end of the carrier. The cigarette and the lighter are configured such that when the cigarette is inserted into the lighter and as individual heaters are activated for each puff, localized charring occurs at spots about the cigarette in the locality where each heater was bearing against the cigarette (hereinafter referred to as a "heater footprint"). Once all the heaters have been activated, these charred spots are closely spaced from one another and encircle a central portion of the carrier portion of the cigarette.
When we included cut filler with the hollow structure of the cigarette in U.S. Pat. No. 5,666,978, it was discovered that such cigarettes when fully filled with cut filler tobacco tended to operate adequately in an electrical lighter for the first several puffs. Thereafter, its delivery would tend to taper off. The same phenomenon would tend to occur when more traditional cigarettes were smoked in an electrical lighter such as the electrical lighter disclosed in U.S. Pat. No. 5,666,978.
When left unfilled, the hollow cigarette structures of the preferred embodiments of U.S. Pat. No. 5,666,978 were also somewhat vulnerable to collapse from extreme or rough handling.